12 Facts About the Five
Heart Rate Zones

There are some special
characteristics of the five heart zones that make them what they are. The key
fact is that a different thing happens in each of the different heart
zones. This means that you have to train in different zones to get each of the
different benefits.

Fact #1. Zones have
size. The size of each zone is a 10% range of your true Max
HR. The size of the zone in number of beats depends on how high your true Max
HR is. Given a 200 bpm Max HR (which is very convenient for multiplying), each
of the five zones would be 10% of 200, or 20 beats wide. Most zones for most
people range from 15 to 20 beats in size; this is big enough to allow for some
"wiggle room" when you are working out, but small enough to be on target for
your particular training goal(s).

Fact # 2. Zones have structure. A zone may be
viewed as being made up of two different parts: its top and bottom halves. In
other words, inside every zone is an upper and and a lower zone. So, while the
whole Aerobic zone may be from 70% to 80% of your Max HR, the lower half of the
zone is 70%-75% (or 140-150 bpm in our 200 bpm Max HR example), and the
upper Aerobic zone is 75%-80% (or 150-160 bpm in this case). It's just a way to
subdivide a medium-sized window into two smaller, even more focused parts.

Fact #3. Zones have dividing
lines. The upper and lower limits of each zone coincide with
the floor and ceiling of its bordering zones. The floor or bottom of the 23
Aerobic zone, for example, is 70% of your Max HR. This floor, or lower limit is
that heart rate where you first break into this zone. Seventy percent of your
Max HR also happens to be where the Fat Burning zone ends. The Aerobic zone
ceiling, 80% Max HR, is the line at the very top or threshold of the zone. At
this point you are passing through the Aerobic zone ceiling into the floor of
the next higher and more intense zone, the Anaerobic zone.

Fact #4. Zone names correspond with their
benefits. Each zone has a specific benefit that comes from the
physiological activities that happen when you exercise within that heart rate
zone. For example, the 21 Healthy Heart zone is exactly that, the range of
heart rates where most individuals realize the most cardiovascular benefits,
leading to improved heart and lung function.

Fact
#5. Zones have numbers. There are certain specific and
measurable events that are so exact that they're represented by a single
heartbeat value called a heart rate numbers. You may already know a few of
them: the maximum heart rate number and resting heart rate number are specific
heart rate numbers that are located in relationship to (inside or on the
dividing lines of) the zones. For example, the diagram below is the
location of your Max HR on the ceiling of Zone 5.

Fact #6. Zones are a subset of the wellness
continuum. The wellness continuum consists of three areas of
physical well-being--health, fitness, and performance--and we need to keep in
mind that we're not all going to have our goals in the same areas. This is why
your friend, who's a veteran marathoner, might complain about what kind of
"shape" he or she is in, while you would kill to look the way they do and be so
fit and healthy. The health area covers those training zones that promote
health but don't primarily improve physical fitness and certainly not
performance. To measure improvements in health, we seek positive changes in
blood pressure, body fat, cholesterol, etc. To measure improvements in fitness,
however, it's positive changes in oxygen utilization, lactate concentrations
and heart rate points we're looking for. And, to measure improvements in
performance, positive changes in completion times, accuracy of movement skill,
mental attitude, and other indices are used.

The Wellness Continuum and the Five Heart Zones Zone Name
Percentage of Max HR Wellness Continuum Perceived Exertion Difficulty

Fact # 7. Zones use
time, not distance, as their measurement tool. That is, the
amount of time you spend in the zone is the way you measure your workout, not
in miles run, or the number of strokes per minute cycled or rowed. This
measurement is called "time in zone" and is measured in the minutes that you
spend in each zone. For example, one day you decide to run for 30 minutes in
the Aerobic zone; the following day you might choose to walk for 50 minutes in
your Fat Burning zone. Varying your workouts, both in activity and zone, allows
you to get multiple benefits from your training.

Fact # 8. Zones have specific numerical values, they are
weighted. When we talk about "exercise by the numbers," that
means doing workouts based on the specific numbers that make up your exact
zones. For example, if your true, tested Max HR is 200 beats per minute, and
you wanted a high fat-burning day as a percent of your fuels burned, you would
calibrate that workout to be in Zone1-Z3. If you really wanted to fine-tune
your training, you might choose to narrow the window to Zone 3. Use the
following chart to determine the specific numerical values for your five
zones.

Fact #9. Higher zones require less
time in zone than lower zones. At the lower zones--or "cruise"
zones as they are sometimes called--you can train in zone for longer periods of
time. But, as you move up to higher intensity zones, you need to decrease the
amount of time that you spend in that zone, particularly in the top two, the
Anaerobic and Redline zones. This simply makes sense--you can walk farther than
you can sprint, and overdoing it is nearly a guarantee of injuries or
burnout.

Fact # 10. Zones are
relative. Your five heart rate zones are specific to your
maximum heart rate, not anybody else's. With two runners, each maintaining a
heart rate of 160 bpm, one might well be in their Z4 Threshold Zone and the
other may be in their Z2 Temperate Zone. It's all relative.

Fact #12. Fat is burned differently in each of the
heart zones. You'll burn a different ratio of fat to
carbohydrates in each of the heart zones. Remember, once you've crossed over
the exercise intensity threshold called "anaerobic threshold" you are burning
no additional fat, though you still burn fat. That's because oxygen has to be
present for fat to burn. If there's no additional oxygen present, there's no
additional fat burned.

One of the foundation principles of
Heart Zone Training is that we need to train in different heart zones to get
different benefits. Here are 12 facts that make that principle clear. There is
no one "training zone". There is no one "target zone". Those are old training
concepts that have been shown not to fit with the way the body really trains.
In fact, there are multiple zones that provide multiple and varied benefits.
Train in the zones that most fit your goals: health, fitness or
performance.